Sunday, April 29, 2012

Cell Bar Qualify CBQ

Value range:   Yes(1) , No(0)
Unit: None
Content: Cell Bar Qualify. CBQ only affects the selection of cells but is not related to cell reselection. It works with CBA to define the access priorities of cells.
Recommendation:  No.
For the area overlapped by cells, the operator often wants MS to preferably select certain cell during cell selection according to the cell capacity, traffic and cell functions, i.e. setting the cell priority. This function can be implemented by setting parameter “cell bar quality”. It works with parameters “cell bar access” to determine the priority of the cell.
CBQ   CBA     Cell selection priority  Cell reselection priority 
 No  Yes          Normal            Normal 
 No  No          Disabled           Disabled 
 Yes  Yes             Low             Normal 
 Yes  No             Low             Normal 
Usually the priorities of all cells should be set as “Normal”. But in some special cases such as micro-cell and dual-band network, the operator may expect MS to preferably enter the cell of a certain type. In this case, the network operator can set the priority of this type of cell as “Normal” while setting the other cells as “Low”. MS will select the cell with lower priority only when there is no appropriate cell with the priority as “Normal During the network optimization by means of cell priority, it is necessary to note that CBQ only influences the cell selection. Therefore, in order to achieve the target, C2 (cell reselection parameter) must be taken into consideration.

 Application of CBQ

Cell Bar Qualify CBQ  
Each circle in the diagram indicates a cell. For some causes, the traffic in cell A and that of cell B are obviously higher than those of the adjacent cells. To make the traffic of the entire area distributed on average, set the priorities of cell A and cell B as “Low” and those of other cells as “Normal”. In this way, the services in the shadow areas in the diagram will be shared by the adjacent cells. It must be pointed out that this setting will reduce the actual coverage areas of cell  A and cell B, which is different from decreasing the transmitting powers of cell A and cell B.


  1. Also decreased the SDCCH Drop after set CBQ=LOW and CB=NO .

  2. Thanks .please check it, is the CBQ and CBA combination for priority setup of cells correct or not? I doubt.